Oven cleaning method and product

ABSTRACT

THE APPLICATION OF CERTAIN OXIDATION CATALYSTS TO BAKEDON FAT DEPOSITS ON OVEN SURFACES REDUCES TEMPERATURE OF COMPLETE DECOMPOSITION. OVEN CLEANING COMPOSITIONS CONTAINING METAL ACETYLACETONATES, HOPEALITE CATALYST, SODIUM CARBONATE, COBALTO-COBALTIC OXIDE, MANGANESE DIOXIDE, PLATINUM METALS AND COMPOUNDS OF PLATINUM METALS, ALONE AND IN COMBINATION WITH SURFACE ACTIVE AGENTS, PENETRANTS AND CATALYST PROMOTERS SUCH AS FREE ALKALI, ARE DESCRIBED.

AU 165 EX 3,684,576 Patented Aug. 15, 1972 day high temperature ovens,i.e., significantly below 800 3,684,576 F., by applying to the baked-onresidue an oxidation OVEN CLEANING METHOD AND PRODUCT Howard Eisen, FairLawn, N.J., and Joseph A. Feighan,

Cheltenham, Pa., assignors to Glamorene Products Coromfion Clifton NJ 5to our invention we have provided a substance which Braking czmfim'mfionof application Ser. can be applied to an oven surface to cause baked-onfat 619,574 M 1 1967. This application Jam 30, residues to more rapidlyoxidize andwaporize at a tem- 970 s 7 3 1 perature near the maximumoperating temperature of I t, (:1, (323 1/00 present-day conventionalovens, i.e., 450-520" F. The US. Cl. 134-2 7 Claims catalyst system willlower the temperature at which cleaning occurs from 800 F. down totemperatures b'plow 600 F. and in some cases, as low as 400 F. to 450-"F. ABSTRAT OF THE DISCLOSURE Studies of air oxidation of the glazed fatdeposits The application of certain oxidation catalysts to bakedfound indirty Ovens, in absence of yh h on fat deposits on oven surfaces reducestemperature of dcfnollsn'ated that P "moval of 5 y completedecomposition. Oven cleaning compositions conoxldijllon the Substancflfollows a p ure-time taining metal acetylacetonates, hopcalitecatalysts, sodium l'elatlonshlp- A! Complete OXldatlOn carbonate,cobalto-cobaltic oxide, manganese dioxide, of fat fieposlts to a PSteel. Surface wmfilke platinum metals and compounds of platinum metals,alone F mlnllteth Rcduclflg the {emperamre 3 and in combination withsurface active agents, penetrants "q from {mnutes 0f heallflg i0 andcatalyst promoters such as free alkali, are described. achleve the 5mmComplete OXIdatlOn, and at (797 F.) complete oxidation occurs inapproximately 45 minutes. At 400 C. (752 F.) complete oxidation re- Thisapplication is a continuation of Ser. No. 619,574, quires one 9 P 45 Iand at fil d Man 1, 19 7, now d d 25 complete oxidation requires about 6hours.

This invention relates to a method of cleaning surfaces l belPw lmlePraclical Oven having a tightly-adhering film of baked-on fats and F 8Pf 15 Obtalfled- At thfifc greases, and to a product for assisting incarrying out 18 mile ible effect after 6 hours, and at 200 C. (392 thismethod. More particularly, the invention relates to f $8 8 Visibleeffect 43 ou an oven cleaner and to a method f cleaning oven 30 Theoxidation catalysts found useful according to this one of the mostdisagreeable tasks f ing the house. invention include certain metalderivatives of 2,4-pentanewife is the periodic cleaning of the oven ofher kitchen dlonfl. also called eta acelylflceiolnalfish cobalt, stove.Ovens accumulate baked-on deposits of various Vanadyl and mflfllaneiflsalts Particularly usefulfood origin which adhere tightly to the enamelsurfaces amP1es s s)a 'of the oven. The deposits are organiccarbonaceous materials, and most usually result from the spattering of(CH'COCFCOCHSMQ fats and oils from foodstuffs during cooking thereof.(CH,COCHCOCH,),Mn, (CH,COCHCOCH,),Mn, and Proteins and carbohydrates mayalso contribute, but (Cl-LCOCHCOCHQNO. usually to a lesser extent. Thesedeposits form a lacquer- 40 Other oxidation catalysts found usefulaccording to like i which extremely diffiwll Wi h the invention includethose known as hopcalite type catordinary soap and water. alysts, inmodified form. One such catalyst, prepared as One current solution tothis problem is an oven which described in Kearby in "Preparation andDevelopment is built with suflicient insulation and the appropriate ofCatalysts," Standard Oil Development Co., Linden, equipment to operateat a temperature of about 800' F. N.J.-Repcrt No. CD-SP-S 1, has anapproximate com- Under this extreme temperature, the baked-on residuesposition of MnO,, 30% Q10, 15% C0 0,, 5% are rapidly oxidized andvaporized, leaving only a resi- Ag,0. Each compound is separatelyprepared by precipidue of fine ash. tation in a water solution, thenbrought into slurry and The other current approach to the probleminvolves mixed. The a o is precipitated onto the slurry of the th f a vl aner which is applied by the house- 50 first three. The sample is thenwashed three times, dried wife and which is formulated to dissolve thedeposit, or in an oven at 140 C. and powdered. at least soften it sothat it can be wiped awsy. Another group of catalysts which is usefulaccording to The cleaner may be one of two general typ s. One thisinvention are the platinum metals, including type, which is marketedvariously as a jelly, a paste or an platinum, ruthenium, rhodium andpalladium. Catalytiaerosol composition, relies heavily upon free alkalias its cally active compounds of these metals may be used, such activeingredient. The second basic type of oven cleaner as the oxides,.cerates, manganates or manganites, chrorelies upon methyl chloride orsome similar solvent and t or h it d d m the compositions y include v nsstem! or agents Other suitable catalysts include Na,co,, 00,0,(codesigned to lift the baked-on fat layer away from the balto-cobalticoxide) and MnO,. surface of the oven. Thus, the catalysts suitable foruse according to this The oven cleaners based on strong alkali aregenerally invention ar those from the group consisting f the successfulin that they will clean the surface of the oven metal acetylncetonates,hopcalite catalysts, sodium carif used properly. It is well known, hwer, that their use bonate, cobalto-cobaltic oxide, manganese dioxide,is extremely messy and is hazardous to the extent that platinum metalsand compounds of platinum metals. severe burns may result if the cleanercomes in contact 66 These catalysts are useful by themselves or withwith the skin of the user. The solvent-based cleaners, on diluents, suchas carbon. Each of these materials can the other hand, are efiectiveonly for fat which has not also be used in various admixtures with eachother to yet burned onto the surface of the oven. Once the latterprovide various desired effects. Coloring materials may has occurred,the solvent-based cleaner is ineffective. be employed, and variousmasking agents may be used We have now found that the baked-on depositon the 70 to avoid unwanted colors.

oven surface may be removed by heating to temperatures significantlybelow those temperatures used for presentcatalyst which has the effectof reducing the temperature at which oxidation of the surface filmoccurs. Accoring In certain cases, it has been advantagesous to employsmall aniounts of catalyst promoters with the catalyst described above.Particularly good results have been obtained with the catalysts modifiedwith potassium hydroxide and sodium carbonate as alkaline promoters.Sucrose and manganese dioxide have also been useful in this capacity.Generally speaking, a level of about 1% of promoter based upon theweight of the catalyst has been used to advantage.

The catalyst described above may also be advantageously supported oncarriers such as chromia and alumina. Methods for obtaining chromia typecatalysts are described in the article by Feighan and Davis, Journal ofCatalysis, vol. 4, p. 594, 1965. Preparation of this type catalyst isaccomplished by depositing a catalytically active substance, such as ametal acetylacetonate, on the base ceramic material in accordance withprocedures known in the art.

The catalyst of the present invention is most conveniently applied tooven surfaces as a paste or gel containing a uniform suspension ofcatalyst, catalyst promoter and other desired ingredients, includingsurfactant, thickener, oxygen donor and extender.Triton X-lOO is asuitable surfactant and penetrant, and may be used at a level up toabout 0.5%. A level of 0.1% is preferred. Triton X-100 is an alkyl arylpolyether alcohol, i.e., actylphenol condensed with moles of ethyleneoxide. Sugar-based surfactants, such as certain sucrose derivatives, aswell as polyoxyethylated compounds, may also be used. Suitablethickeners include carboxymethyl cellulose, methyl cellulose, andPolyox, a trade name for a water-soluble, highly polymerized ethyleneoxide. A suitable oxygen donor is KNO; preferably at a level of 0.5%.Suitable extenders include sodium aluminate and sodium silicate --Al,0,,preferably at a 0.5% level. Other additives, promoters, color pigmentsand the like may be used. Suitable thickeners includecarboxymethyllevel. The balance of the composition is liquid andpreferably is water.

The following examples further illustrate the process of this invention.

EXAMPLE I The efiectiveness of various oxidation catalysts in removingbaked-on fat deposits was assessed using the procedure described below.Stainless steel plates, 1" x 4" in size and approximately ,4 thick, werehighly polished to present a nonporous surface. These plates were coatedwith layers of animal fats by brushing the fat onto the surface. Theplate was then heated to cause partial decomposition of the fat. andsuccessive layers were deposited. The deposited material was then heatedin a Fisher burner in an open flame at temperatures appzoaching 800' C.until a hard glazed coating of dark brown to black coloration wasobtained, similar to carbonized fatty solids found in ovens.Approximately 2-4 mg. of fat were deposited per square centimeter ofplate surface.

Powdered catalyst was applied to about 40% of the total plate surface,the balance of the plate acting as a control. To assure an even coatingof catalyst, the fat deposit was first moistened with a thin film ofalcohol. The dry catalyst was then rubbed or spread on the fat deposit.The solvent aided the dispersion process and on drying gave a relativelyeven catalyst deposit. Where catalysts activators, such as sodiumhydroxide and sodium carbonate, were used the activators were dissolvedin the alcohol as a 1% solution and applied directly to the fat deposit.

The stainless steel plates with the fat deposit and catalyst thereonwere then heated for specified lengths of time at specifiedtemperatures. On completion of the heat treatment, the activity of eachcatalyst was evaluated in accordance with the following visual ratingsystem:

A-no effect noticeable-fat deposit still glazed. Bbare1y detectableeffect on fat deposit. C-intermediate effect on fat deposit, surfacedisrupted.

4 Dstrong effect, some small amount of steel surface visible. E-surfacemetal easily observable, large portions of surface cleaned.

Table 1 below summarizes the results obtained.

TABLE 1 Catalyst Temp, Time Catalyst promoter C. (hrs) Rating 400 c 40oc 400 14 D 300 is C 300 34 E 400 M D 400 x E 400 x E 350 i 1)Mll02'N82COs.... 350 l D MnOyKOiL. 350 1 C 300 1 ii 300 l B 300 1 A 3601 D 360 1 11 850 1 11 300 l A 800 1 B 300 1 B NBzCOs 270 a C NBICOrMIlO270 3 C MnOrKOI'L. 270 8 B 800 l D NazCOs B00 1 I) 270 8 C NarCOs 270 8C M110: 850 l C MnO NmCOi 360 l B 800 836 C Na:CO 800 2 B MnOrNazCO 3002 B MnOz-Kolln 800 2 B NazCO 800 8% O O 300 8}? C M110: 860 E MnO; B008% B PtonO MnO1-Ns;C0;.... 800 1 B MnO: 30% Duo, 15% 00101. 6% M10; M10precipitated onto slurry st ilrst three.

EXAMPLE II A series of oxidation catalysts were prepared and evaluatedas agents for removing baked-on fat deposits. For this series, a numberof stainless steel sample pans approximately 1" in diameter, and havinga ,4 lip were cleaned in hot potassium hydroxide solution, rinsed welland then air dried. The interior surface of these pans were then coatedwith animal and vegetable fat. The greased pans were heated at 350' C.for approximately 30 minutes in a tube furnace with free access of airto form a hard glazed deposit of fat having up to about 60 mg. persquare centimeter.

A dry, powdered catalyst was added to each pan, and slurrled in the panwith a few drops of methyl alcohol to obtain a coating of uniformthickness over the fat deposit. The deposit was then air dried forseveral hours to remove the solvent. Duplicates of each sample were thenheated for two hours, one at 232 C. and the other at 288' C. and theweight loss occasioned by volatilization by the fat deposit wasdetermined. Table 2 below summarizes the results obtained in thesetests.

TABLE 2 Catalyst Promoter EXAMPLE m A suitable composition for use as anoven cleaning composition according to this invention has the followingformula:

Water, balance.

The composition is prepared by mixing the ingredients to form a paste.The paste is used by applying it to the surface of an oven havingbacked-on fat deposits and operating the oven at its maximum temperaturefrom two to three hours.

We claim:

1. A method of removing a deposit of baked-on fats from oven surfacescomprising the steps of (1) applying to the deposit an oxidationcatalyst selected from the group consisting of the cobalt, manganese andvanadyl acetylacetonates and soidum carbonate, and (2) heating thedeposit for a time and at a temperature suflicient to cause completeoxidation of the deposit.

2. The method of claim 1, wherein the catalyst is applied to thebaked-on fat deposits of an oven as a uniform suspension of powderedcatalyst in water.

3. The method of claim 2 wherein the suspension of catalyst in wateradditionally contains a catalyst promoter selected from the groupconsisting of potassium hydroxide, sodium carbonate, sucrose, andmanganese dioxide, at level of about 1%, based on the weight of thecatalyst.

4. An oven cleaner consisting essentially of an oxidation catalystselected from the group consisting of the cobalt,

manganese and vanadyl acetylacetonates and sodium carbonate, which willcatalyze the oxidative deterioration of baked-on fat deposits at atemperature below about 600 F. within a three hour period of time.

5. The oven cleaner of claim 4, wherein the composition additionallycontains a nonionic surface active agent and a catalyst promoterselected from the group consisting of potassium hydroxide, sodiumcarbonate, sucrose, and manganese dioxide, at a level of about 1% basedon the weight of the catalyst.

6. An oven cleaner adapted for use in oven cleaning processes conductedat a temperature below 600 F. within a one hour period of timeconsisting essentially of cobaltous acetylacetonate as an oxidativecatalyst and about 1% by weight of the catalyst of potassium hydroxide.

7. An oven cleaner in the form of a paste adapted for use in ovencleaning processes consisting essentially of 0.1% of an alkyl arylpolyether alcohol as a penetrant, 0.5% methyl cellulose as a thicknener,0.5% catalyst of cobaltous acetylacetonate with about 1% by weight ofthe catalyst of sucrose and potassium hydroxide, 0.1% miscellaneouscolor pigments and a balance of water.

References Cited UNITED STATES PATENTS 3,266,477 8/1966 Stiles 126-2733,271,322 9/1966 Stiles 252-428 3,460,523 8/ 1969 Stiles et a1. 126-193,498,927 3/1970 Stiles 252-451 3,549,419 12/1970 Stiles 134-2 MAYERWEINBLA'IT, Primary Examiner- U.S. Cl. X.R.

P0405) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION tent No-,576 Dated August 15, 1972 Inventor) Howard Eisen and Joseph A. FeighanIt is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

' Col. 2, lines 34 and 35, the formula should be on one line as follows:-(CH3COCHCOCH3) 2C0, (CH3COCHCOCH3) Co,-;

Col. 3, line 25, "actylphenol" should be -octylphenol-;

Col. 3, line 31, after "KNO insert a comma I Col. 3, line 35, delete".Suitable thickeners include carboxymethyl-" and insert --at levels up tol/8%, and preferably a O.l%--;

Col. 5, line 16, "backed-on" should be bakedon-;

Col. 5, line 24, "soidum" should read --sodium--;

Col. 5, line 34, before "level" insert -a; and

Col. 6, line 19, "thicknener" should be --thickener.

Signed and sealed this 27th day of March 1973.

(SEAL) Attest:

EDWARD M.PLETCHER,JR. RoBEP T (EOTTSCHALK I Attesting OfficerCommissioner of Patents

